Embodiments of the present technology generally relate to ultrasound transducers configured to provide improved thermal characteristics.
As depicted in FIG. 1, conventional ultrasound transducers 100 can be composed of various layers including a lens 102, impedance matching layers 104 and 106, a piezoelectric element 108, backing 110, and electrical elements for connection to an ultrasound system.
Piezoelectric element 108 can convert electrical signals into ultrasound waves to be transmitted toward a target and can also convert received ultrasound waves into electrical signals. Arrows 112 depict ultrasound waves transmitted from and received at transducer 100. The received ultrasound waves can be used by the ultrasound system to create an image of the target.
In order to increase energy out of transducer 100, impedance matching layers 104, 106 are disposed between piezoelectric element 108 and lens 102. Conventionally, optimal impedance matching has been believed to be achieved when matching layers 104, 106 separate piezoelectric element 108 and lens 102 by a distance x of about ¼ to ½ of the desired wavelength of transmitted ultrasound waves at the resonant frequency. Conventional belief is that such a configuration can keep ultrasound waves that were reflected within the matching layers 104, 106 in phase when they exit the matching layers 104, 106.
Transmitting ultrasound waves from transducer 100 can heat lens 102. However, patient contact transducers have a maximum surface temperature of about 40 degrees Celsius in order to avoid patient discomfort and comply with regulatory temperature limits. Thus, lens temperature can be a limiting factor for wave transmission power and transducer performance.
Many known thermal management techniques are focused on the backside of the transducer in order to minimize reflection of ultrasound energy toward the lens. Nonetheless, there is a need for improved ultrasound transducers with improved thermal characteristics.